Who doesn’t love a large, firm tomato warmed by the summer sun? I do and the more I get each season, the better. There are various tips and tricks available to get a bumper harvest of tomatoes, but one of the most effective is companion planting tomatoes with their favorite plant friends.
With the right combination of plants, tomatoes can be healthy, strong and provide you with an abundant harvest. Who doesn’t want more tomatoes?
But what plants go with tomatoes? Well, there are a lot. There are also plenty of plants that shouldn’t be close to tomatoes. Let’s explore.
Perfect Conditions For Tomatoes
One of the ways I find the perfect companion plant is to know what the perfect conditions for the main plant are and then look for other plants that can thrive in those conditions. If the conditions aren’t right for all the plants, interplanting generally won’t work.
Tomatoes love full sun for the majority of the day. They like temperatures between 65-75ºF. A soil pH of 6.3 to 6.8 is needed and you need to keep it moist.
Now we have our basic baseline, let’s look at the plants that thrive with tomatoes and help tomatoes provide a bumper harvest.
Best Companion Plants For Tomatoes
There are many plants that do well with basil, depending on your needs and goals. Here are some of the best options:
This is a classic combination I always go for first. It’s said that basil improves the flavor of tomatoes. Basil also repels mosquitos and fruit flies. Tomatoes surrounded by basil are often bigger too.
Bonus! Pick a sweet cherry tomato and wrap a basil leaf around it to munch on while gardening.
While underappreciated as a food crop, borage can repel the dreaded tomato hornworm. (Manduca quinquemaculata). As something that can beat a pest that can defoliate a tomato plant, borage is an important addition to a tomato garden.
Be aware though, that once you plant borage, it seems to pop up all over the garden and yard. Also, if you have bees, you know how much they love borage.
When planted with tomatoes (and any other plants), garlic will repel red spider mites. Garlic also has antifungal properties, helping to keep the soil healthy. Provide both tomato plants and garlic with plenty of water.
Tomatoes and lettuce remind me of summer, so it makes sense they grow well together and help each other out. Lettuce gets much-needed shade from tomato plants. Tomato plants have the benefit of soil being kept moist and cool by the lettuce.
To improve the flavor of tomatoes. many gardeners also plant mint. Make sure to give the mint plenty of water (along with watering the tomatoes) to avoid rust taking hold. More so than borage, mint can become invasive, so plant in pots on top of the soil or buried in the garden.
Strongly scented chives benefit tomatoes in many ways. They improve the taste, size, and general health of tomatoes, and may make the need for fertilizer for tomatoes less. Chives deter aphids, which love tomatoes. They also deter Japanese beetles.
Grow parsley near chives and tomatoes for the best results, but keep parsley away from any mint. Parsley helps the growth of tomatoes and hoverflies are attracted to parsley.
Hoverflies love to chew on aphids, which are fond of tomato plants. Use the parsley to attract this helpful insect to address aphid issues.
With its bright, grain-like seeds and big leaves, amaranth looks cool. I’ve just started growing it and I love planting it with tomatoes. Amaranth attracts beneficial insects to the tomato garden. Amaranth is actually a host for predatory beetles who feed on tomato plant pests.
To repel flea beetles from tomato plants, couple it with sage. If spider mites are a problem for you, use sage, and for an extra boost, add some cilantro as well.
One of my gardening theories is if foods go together on a plate, they go together in the garden. Cucumbers and tomatoes pair perfectly in salads and many other dishes. If you have tomatoes growing in a greenhouse, cucumbers match perfectly. They also marry well in the garden.
Two reasons they grow so well together is because they require the same soil conditions, and they take the same amount of time to grow.
Onions are related to chives and garlic, and make for great companions. They all omit an odor that repels many of the pests that plague tomatoes.
Whether they’re hot peppers or sweet ones, they go well with tomatoes. Many plants from the nightshade family, like tomatoes, grow together (except tomatoes and potatoes).
Planting with tomatoes is actually beneficial for arugula. The tomatoes shade the garden where arugula grows.
Tomatoes and carrots grow at around the same pace. Plant carrots when the tomato plants first go in. The carrots will be ready just before the tomatoes are ready and take over the area.
Just make sure you don’t plant the carrots too close to the tomato roots. Pulling them out will disturb the roots, and if you time it right, the carrots will be pulled before the tomatoes are ready.
This is a combination not often chosen, but it works. Keep the asparagus away from the stem of the tomato plant. To make it even more likely the tomatoes succeed, underplant the asparagus with parsley and basil.
Tomatoes omit a chemical called solanine. This repels a beetle that attacks asparagus. Funnily, it’s called an asparagus beetle.
To help the tomato plant out, asparagus omits a chemical that deters another prolific pest, nematodes.
This trade-off between plants is the perfect example of companion planting.
Sometimes known as pot marigold, calendula can assist in repelling tomato pests away. Hornworms and whitefly both hate calendula so if you have suffered from these pests previously, try this winning combination.
Plants to Avoid Putting With Tomatoes
These are the plants you should avoid planting with your tomatoes.
This combo contradicts the idea that plants that taste good together should grow together.
Tomatoes are hungry feeders and so is corn. You really need to stay on top of the soil nutrients with both these plants and they will cause the other to struggle given half the chance.
Corn also attracts pests that attack tomato plants like the tomato fruit worm (also known as the corn earworm). The larvae can decimate your corn crop, and then move to the tomatoes. They will tunnel into all parts of the plant including the leaves, stems, and tomato fruit.
The tomato fruit worm (Heliothus zea) is nearly impossible to deal with once it has burrowed into the plant and fruit.
Tomato and fennel don’t get along because fennel can affect the growth of tomatoes and cause them to be stunted. Fennel roots release a chemical that affects other plants’ abilities to grow properly. Give fennel its own space.
Because both potatoes and tomatoes are so closely related, they compete for the same nutrients. They also suffer from the same pests and diseases a lot of the time, including the potato psyllid and blight.
Although I’ve grown brassicas with tomatoes before, the resulting tomato harvest was nowhere near as good as if I hadn’t. Fungal diseases that brassicas suffer from also affect tomatoes. If you put your tomatoes and brassicas in one space, the chances of disease are higher.
Brassicas also require very nutrient-rich soil like tomatoes, so if they end up weakened due to them all competing for food, the chances of infection are higher.
Brassicas to not plant with tomatoes include:
- Brussels sprouts
Rosemary grows well with the brassica family but doesn’t work with tomatoes. Both the tomatoes and rosemary seem weaker than if they weren’t together.
Tomatoes and dill are good friends in their youth, but they grow apart as they age. Older dill can stunt the growth of tomatoes. It’s better to keep them apart.
Although eggplant can technically grow with tomatoes, it’s more of a health issue that can cause problems. Early and late blight affects both plants. early blight kills leaf tissue, meaning less fruit to harvest because of a lack of photosynthesis.
Late blight affects the whole plant and likely remains in the soil. Not only should you not plant eggplant and tomatoes together, but don’t plant eggplants in the same soil as tomatoes for two years.
This is a far less common combination, but tomatoes are affected so badly by walnuts that you should dispose of walnut shells and flesh in the garbage, and not put them in your compost.
If you have a walnut tree near your vegetable garden, or even over-hanging it, most plants are affected by a chemical called juglone. This is often toxic to plants and can inhibit their growth.
Members of the Solanaceae family, like tomatoes, are particularly susceptible to juglone and they will definitely struggle to grow.
How Close To Plant Tomato Companions
To embrace companion planting, the next question is how close do we plant the friends to the tomato crop, and how far away should the enemies be?
A good rule of thumb is to plant friends next to each other, or within two rows. Those that don’t suit being planted together should be at least three to four rows apart.